Intracloacal inoculation, an effective screening method for determining the efficacy of probiotic bacterial isolates against Campylobacter colonization in broiler chickens

Authors: ARSI, K - University Of Arkansas; Donoghue, Ann - Annie; WOO-MING, A - University Of Arkansas; BLORE, P - University Of Arkansas; DONOGHUE, D - University Of Arkansas

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2014
Publication Date: 1/1/2015
Citation: Arsi, K., Donoghue, A.M., Woo-Ming, A., Donoghue, D.J. 2015. Intracloacal inoculation, an effective screening method for determining the efficacy of probiotic bacterial isolates against Campylobacter colonization in broiler chickens. Journal of Food Protection. 78:(1)209-213.

Interpretive Summary: Campylobacter is a leading cause of foodborne illness worldwide. It is common in poultry, and human infections are often associated with consumption of contaminated poultry products. One strategy to reduce Campylobacter colonization in poultry is by using oral probiotics. Unfortunately, oral probiotics produce variable results, possibly due to destruction in the acidic environment of stomach. Protection (e.g., encapsulation) of isolates may overcome this problem but there is no assurance these isolates will have efficacy in the lower gastrointestinal (GI) tract. Therefore, screening candidate isolates by directly placing them in the lower intestinal tract via cloacal inoculation may eliminate the time and expense of encapsulating ineffective isolates. Thus, the purpose of this study was to collect bacterial isolates with anti-Campylobacter activity in vitro and evaluate their efficacy in vivo upon either oral or intra-cloacal administration. Bacterial isolates were collected from healthy birds and evaluated for efficacy against Campylobacter in vitro. Isolates identified as generally regarded as safe (GRAS) status and demonstrating in vitro anti-Campylobacter properties were evaluated after oral or intra-cloacal inoculation into day of hatch chicks (n=10 birds/isolate/route of administration). On day 7, birds were orally gavaged with a 4 strain mixture of wild type Campylobacter. On day 14, birds were euthanized and the ceca were collected aseptically for Campylobacter enumeration. When isolates were dosed orally, only one isolate had a 1 log reduction in cecal Campylobacter counts, whereas when administered intra-cloacally, six of these isolates produced a 1-3 log reduction in cecal Campylobacter counts in 14 day old chickens. These results support the strategy of evaluating the efficacy of potential probiotic isolates via cloacal inoculation prior to undergoing the effort of protecting isolates (e.g., encapsulation) for oral administration.

Technical Abstract: Campylobacter is a leading cause of foodborne illness worldwide. It is common in poultry, and human infections are often associated with consumption of contaminated poultry products. One strategy to reduce Campylobacter colonization in poultry is by using oral probiotics. Unfortunately, oral probiotics produce variable results, possibly due to destruction in the acidic environment of stomach. Protection (e.g., encapsulation) of isolates may overcome this problem but there is no assurance these isolates will have efficacy in the lower gastrointestinal (GI) tract. Therefore, screening candidate isolates by directly placing them in the lower intestinal tract via cloacal inoculation may eliminate the time and expense of encapsulating ineffective isolates. Thus, the purpose of this study was to collect bacterial isolates with anti-Campylobacter activity in vitro and evaluate their efficacy in vivo upon either oral or intra-cloacal administration. Bacterial isolates were collected from healthy birds and evaluated for efficacy against Campylobacter in vitro. Isolates identified as generally regarded as safe (GRAS) status and demonstrating in vitro anti-Campylobacter properties were evaluated after oral or intra-cloacal inoculation into day of hatch chicks (n=10 birds/isolate/route of administration). On day 7, birds were orally gavaged with a 4 strain mixture of wild type Campylobacter. On day 14, birds were euthanized and the ceca were collected aseptically for Campylobacter enumeration. When isolates were dosed orally, only one isolate had a 1 log reduction in cecal Campylobacter counts, whereas when administered intra-cloacally, six of these isolates produced a 1-3 log reduction in cecal Campylobacter counts in 14 day old chickens. These results support the strategy of evaluating the efficacy of potential probiotic isolates via cloacal inoculation prior to undergoing the effort of protecting isolates (e.g., encapsulation) for oral administration.